Writing instrument



FIG. 1 is a perspective view of a writing instrument;

FIG. 2 is a front elevation view thereof, the rear elevation view is a mirror image thereof;

FIG. 3 is a right elevation view thereof, the left elevation view is a mirror image thereof;

FIG. 4 is a top plan view thereof; and,

FIG. 5 is a bottom plan view thereof.

The broken lines in the drawings illustrate portions of the writing instrument which form no part of the claimed design. 

CLAIM The ornamental design for the writing instrument, as shown and described. 